The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
As is known in the construction art, modern building construction often includes construction of concrete structure with insulated concrete forms (ICF's) that are composed either from a foam insulating material that form permanent concrete form walls or from concrete masonry construction (CMU). ICF construction sandwiches a heavy, high-strength reinforced concrete between two layers of a light, high-insulation foam. This combination creates a wall with an unusually good combination of desirable properties: air tightness, strength, sound attenuation, insulation, and mass. CMU typically utilizes concrete block or concrete brick in the formation of walls.
Concrete structures such as ICF walls and floors are constructed by placing separate ICF building blocks on each other. Rebar is placed within a cavity formed by the ICF blocks. Concrete is then poured and the walls are formed with the ICF blocks being left in place, even after the concrete hardens. The concrete wall so formed can include foundation walls and other building walls. For ICF construction, further insulation is generally not necessary. Additionally, floors and roofs can be poured using ICF construction techniques. CMU walls are formed by laying concrete blocks or bricks as masonry products. CMU and ICF walls can be externally finished such as with veneers, stucco, gypsum boards, and brick on the interior and exterior of the wall as required.
ICF blocks are typically made with two opposing expanded polystyrene side panels that are arranged in spaced parallel relationship with their inner surfaces facing each other to form a cavity therein. Plastic or metal bridging members can be molded into the side panels to hold them together to form the blocks and to hold them against the forces applied by the poured concrete within the cavity. Typically, an end plate is molded within each side panel as an internal “stud” for attachment of finishing materials. The bridges are typically attached to these end plates for structural support during the pouring of the concrete and for anchoring the endplate into the cured concrete. Rebar is often placed horizontally and vertically within the cavities of the ICF blocks before the concrete is poured. The purpose of using rebar is to hold the concrete in compression to provide added strength. CMU blocks or bricks are typically constructed similar to brick walls and typically include mortar between each adjacent CMU unit.
As these ICF and CMU blocks are stacked to form a wall, it is often necessary to form penetrations such as openings for doors, windows, utilities, HVAC ducts and other mechanical systems. These penetrations are often formed with block-out systems known as “bucks” that provide the openings as required by the ICF or CMU construction techniques, such as with an ICF wall before and after the concrete is poured, or before or during stacking of the CMU blocks. As with traditional construction, bucks have been utilized to provide such a block-out opening in the wall. Many of these conventional bucks are removable once the concrete has hardened, similar to the wood forms. These are often referred to as “reusable bucks”.
These bucks are typically built as wooden framed bucks that provide the opening in the wall. These can be removable or can be left in place similar to the ICF or CMU blocks. If left in place after the wall or floor is constructed and cured, this wooden frame of the buck provides a fastening surface for the window or door and its finishing trim. The buck typically retains the concrete and also provides a point of attachment for interior and exterior finishes around the edge of the openings. In order to keep the wood frame properly aligned in the opening within the stacked wall forms, one or more temporary braces can also be used. These typically help to provide alignment of the wall forms with the wood frame. The buck typically requires supplemental bracing inside its frame to prevent deflection of the wood members under pressure from the poured concrete. This is usually accomplished by temporarily placing a brace between one or more sides of the buck opening.
When the buck frame is to be left in the wall, it is typically secured to the concrete by one or more fasteners, such as nails or anchor bolts. These are positioned prior to the pouring of the concrete and are secured to the frame and left hanging between the sides of the penetration during construction. The subsequent construction such as pouring of wet concrete into the cavity of an ICF wall can cause the concrete to flow around the fasteners and partially secure the buck frame in place once the concrete has hardened. Similarly, during CMU construction the mortar typically partially secures the frame to the CMU blocks about the penetration.
Such bucks have been traditionally constructed of wood and plastic. However, these bucks have demonstrated a variety of problems. For instance, wood bucks are known to change dimensions over time as a result of variations in humidity, temperature, and pressure, such as during the actual construction process. Plastic bucks have been shown to deform similarly, especially over time. Additionally, these plastic and wood bucks are not configured to endure substantial stress and do not offer strong bonds to the wall and as such can become easily dislodged from the wall.
As a result of the foregoing problems and disadvantages, there is a need in building construction for a more efficient, cost-effective and reliable systems and methods for finishing doors and windows in concrete walls and ceiling made with insulated concrete forms or concrete blocks.